Questions

PSLV - C37 vehicle was used for ISRO's successfully launch of 104 satellites.

An operating system is a program that acts as an intermediary between the user and the computer hardware. The purpose of an OS is to provide a convenient environment in which user can execute programs in a convenient and efficient manner. It is a resource allocator responsible for allocating system resources and a control program which controls the operation of the computer hardware.

Earth rotates on its own axis and completes one rotation in 24 hours

The chemical composition of a rock is mainly minerals.

Chitra Magimairaj

The objects through which light cannot pass are called as Opaque objects. Some objects allow some light to pass through them and are called as Translucent objects. The objects which allow all the light to pass through them are called as Transparent objects.

Here in the given options Book is an example of opaque object as it does not allow light to pass through it. Water is transparent object and notebook paper and sun glasses are examples of translucent objects.

The air around us is a mixture of gases, mainly nitrogen and oxygen, but containing much smaller amounts of water and other gases.

Earth's atmosphere is composed of many gases. Their percentages by volume is given by::

 
78% Nitrogen,

21% Oxygen,

0.9% Argon, and

0.03% Carbon dioxide 

And very small percentages of other elements.